WASHINGTON, DC. -- Consumers Union, publisher of Consumer Reports, today asked the U.S. Department of Agriculture to retest a cow suspected in November 2004 of having mad cow disease, using a critical, internationally recognized test that the agency failed to use. The test, called the Western blot, is used by authorities in Japan and Europe when making a final determination as to whether a suspect cow has the fatal brain-wasting affliction, which can be passed on to humans.

A Consumers Union delegation met earlier this month with USDA officials and today issued a letter to USDA Secretary Mike Johanns urging the agency to revise its testing methods. CU is asking the agency to retest the November cow using the Western blot and to send samples from the cow to the United Kingdom for an independent evaluation.

Given the potential consequences to both public health and the cattle industry if this brain-wasting disease were to become established here, it is extremely important that every scientifically justifiable step be taken to prevent it, said the letter signed by Michael Hansen, PhD., a biologist with Consumers Union and spokesperson for its www.NotinMyFood.org campaign and Jean Halloran, director of CUs Consumer Policy Institute.

The USDA limited its confirmatory testing in November 2004 to the immunohistochemistry (IHC) test, which it describes as the gold standard. The result of the IHC test was negative. USDA did not perform the Western blot test, even though it had previously used both IHC and the Western blot test in confirming the first U.S. case of mad cow disease, from Washington State in December, 2003. The USDA also sent material from the 2003 Washington State cow to the United Kingdom for further review of its results.

Scientists in Japan and Belgium have reported that suspect cows may be negative on the IHC and still register as positive on the Western blot. Such cows are universally regarded as infected.

The IHC test is more subjective than the Western blot test, relying on the judgment of a skilled scientist is assessing the appearance of thin slices of brain material under a microscope, Hansen said. The Western blot test is more objective, with results that can be read by any technician. In the U.S., the IHC test is performed by a USDA scientist at a USDA laboratory in Ames, Iowa.

The cow USDA assessed in November 2004 had come up as suspect for mad cow disease in two runs of the Biorad quick test. The Biorad test has been used to screen over 200,000 cows for mad cow disease since USDA began a new testing initiative in July 2004. However, all international authorities agree that the Biorad screening test can give a false positive result. Thus it must be confirmed by other tests. CU urges USDA to use both Western blot and IHC for confirmation.

The USDA should operate out of an abundance of caution in its efforts to keep the U.S. food supply safe from (mad cow disease), the letter to Johanns stated. The experience of the United Kingdom, where millions of cattle have been destroyed, beef exports blocked for many years and 147 people have died, painfully demonstrates the consequences of insufficient action to prevent the spread of mad cow disease.

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Consumers Union, publisher of Consumer Reports, is an independent, nonprofit testing and information organization serving only the consumer. We are a comprehensive source of unbiased advice about products and services, personal finance, health nutrition, and other consumer concerns. Since 1936, our mission has been to test products, inform the public, and protect consumers.

We appreciate having had the opportunity to meet with you on February 9, 2005 with the Food Safety Coalition. Because we had limited time on that occasion, we are following up with a letter explaining our concerns on one issue that is especially important to Consumers Union: USDAs bovine spongiform encephalopathy (BSE), commonly known as mad cow disease, testing procedures.

For reasons we explain below, we urge USDA to expand its testing protocol to bring it in line with those of Europe and Japan, by including a test called the Western blot when evaluating cows suspected of mad cow disease, such as the suspect cow identified in November, 2004. Under current USDA testing protocols, it is possible that USDA will miss cases of mad cow disease that could be confirmed through additional testing.

As Secretary of Agriculture, you face the important and very difficult responsibility of preventing mad cow disease in the United States. Given the potential consequences to both public health and the cattle industry if this brain-wasting disease were to become established here, it is extremely important that every scientifically justifiable step be taken to prevent it. It is especially critical to understand to what extent the disease may already be present in the United States, now that one case was discovered in Washington State in December, 2003.

As you know, the USDA has tested some 230,000 cattle since June, 2004, for mad cow disease. Although this seems like a large number, it is still less than 1% of the 35 million cattle slaughtered annually in the US. The number of cows tested should be increased.

Consumers Union also believes that USDAs testing protocol should be expanded. USDAs testing protocol specifically does not include the Western blot test (accompanied by a sodium phosphotungstinic acid [NaPTA] precipitation step), a test used by all European Union countries and Japan. When a cow in the USDA testing program is considered suspect as a result of positives in two runs of the Biorad quick test, as happened in November, 2004, it is sent to the USDA Ames Iowa laboratory for further evaluation. That evaluation includes only an immunohistochemistry test (IHC), which USDA refers to as the gold standard. We disagree with that characterization. Recent studies in Belgium and Japan have shown that the IHC test misses some cases of mad cow disease. A letter in last months Veterinary Pathology, from one of the worlds leading authorities on mad cow disease testing, pointed out that the Western blot, when accompanied by the NaPTA step, is far more sensitive than IHC in detecting the mad cow disease infectious agent .

In fact, USDA used both the IHC and Western blot tests to confirm its first case of mad cow disease, in December 2003. According to a USDA publication, the Western blot test was crucial to identifying that case. It is thus difficult to understand why USDA did not again use the Western blot test along with IHC on its second suspect cow.

We therefore urge you to go back and retest--using the Western blot test with the NaPTA step--the suspect cow that was identified in November, 2004, and to send appropriate material from that cow to the United Kingdom laboratories for an independent evaluation. We further urge you to revise USDA policy and routinely use the Western blot test with the NAPTA step, as well as the immunohistochemistry (IHC) test, for confirmation of suspect mad cow cases.

The USDA should operate out of an abundance of caution in its efforts to keep the US food supply safe from BSE. The experience of the United Kingdom, where millions of cattle had to be destroyed, beef exports were blocked for many years, and 147 people have died, painfully demonstrates the consequences of insufficient action to prevent the spread of mad cow disease.

The trust of American consumers, and of foreign markets, in the safety of American beef, rests on having confidence that USDA is utilizing the best science available, comparable to that used in other scientifically advanced countries.

A copy of a prior letter on this subject, which we sent to Dr. John R. Clifford, Deputy Administrator of the Animal Plant Health Inspection Service, is attached and we understand is in the process of being answered.

We look forward to hearing from you about whether you will direct USDA to retest the November 2004 suspect cow and revise USDA policy to routinely use the Western blot as well as IHC on all suspect animals.